Thermogravimetric Differential Thermal Analysis Research Articles

Robustness of self-compacting concrete incorporating bone china ceramic waste powder along with granite cutting waste for sustainable development

Keeping sustainability at the centre of this work, two solid waste materials have been selected for this study. First is bone china ceramic waste powder (BCCWP) obtained from broken or distorted bone china ceramic waste products, and the second is granite cutting waste (GCW) from the granite cutting and shaping industry. The present study aims at assessing fresh state, mechanical and durability characteristics of the SCC mixes incorporating BCCWP and GCW as cement and fine aggregate replacement, respectively. In a preliminary state, the raw BCCWP was evaluated for various pozzolanic activity tests such as the Frattini test, strength activity index and lime saturation test. SCC mixes were tested for compressive strength, splitting tensile strength, corrosion and chloride resistance tests. SCC mixtures were also tested at elevated temperatures by conducting thermogravimetric analysis (TGA) and differential thermal analysis (DTA) tests. Outcomes of fresh properties were found in the satisfactory limit as per EFNARC standard, except the SCC mix prepared with 30% BCCWP and 40% GCW. SCC mix with 10% BCCWP and 30% GCW showed the maximum strength properties. Moreover, statistical analysis using ANOVA was carried out to find the effectiveness of BCCWP and GCW parameters on various hardened state characteristics. From ecological and economic analysis, lesser embodied energy and embodied carbon dioxide emission, as well as cost reduction, was observed for SCC mixes containing BCCWP and GCW.

Sol-gel synthesis of nano block-like ZnMn2O4 using citric acid complexing agent and electrochemical performance as anode for lithium-ion batteries

Spinel ZnMn 2 O 4 anode material has high research value as a potential alternative anode material for lithium-ion batteries due to the limited theoretical capacity of commercial graphite. This study prepared a block structured lithium-ion battery anode material ZnMn 2 O 4 using the citric acid sol-gel combustion method. The thermal decomposition process of the xerogel precursors was investigated using thermogravimetric differential thermal analysis. When the ratio of citric acid to metal cations is 4:1, the prepared ZnMn 2 O 4 material had an uneven block structure (ca. 0.3–1.3 µm). The material shows high electrochemical performance: the initial capacity is as high as 1100.2 mAh·g −1 at 0.1 C, and the capacity remains at 277.6 mAh·g −1 after 40 cycles. Finally, the first discharge and the second charge–discharge processes of ZnMn 2 O 4 were thoroughly investigated, and the electrochemical behavior in the electrochemical process was analyzed. • ZnMn 2 O 4 block-like structure are synthesized by sol-gel combined combustion method. • Smaller particle size can effectively increase the reactive sites between electrolyte and material. • The optimized sample shows good lithium storage properties.

An intrinsic analysis on the nature of alumina (Al2O3) reinforced hydroxyapatite nanocomposite

Human bones possess a unique capacity to regenerate and regrow. Bone implants are used to support the body and provide time for the bones to heal. Amidst expensive and incompatible bone implants, bone-like hydroxyapatite (HA) is considered as a perfect choice, but its brittle nature makes it unfit. This study aims to rectify this issue, by reinforcing HA with alumina (Al2O3). Hydrothermal method was adopted to form the Al2O3/HA nanocomposite. X-ray Diffraction (XRD) and Fourier-Transform Infra-Red (FTIR) spectroscopy tests validate the basal structure and constitution of the Al2O3/HA nanocomposite. Imaging tests revealed nanorod morphology and thermogravimetric-differential thermal analysis revealed the thermal nature of Al2O3/HA. The mechanical stability of the nanocomposite was scrutinized by a Vicker's hardness tester. Load-displacement curve analyses by means of Onitsch and Kick's power laws were used to find various mechanical parameters. The enhanced nanocomposite proved to be sturdy with a hardness value of 5.2 GPa and a fracture toughness of 1.18 MPam1/2. Thereby, the addition of alumina was found to be advantageous in resolving the brittleness issue of HA.

Comprehensive study on the reduction of biomass embedded self-reducing pellets (SRP) under H2 involved conditions by TG-DTA

Application of biomass embedded self-reducing pellets (SRP) in the Hydrogen direct reduction (H-DR) process is expected to solve the problem of low/zero carbon content in the DRI product of H-DR. In this study, reduction of biomass embedded SRP by N2/H2/CO at different temperatures was conducted by using Thermogravimetric/Differential Thermal Analyzer (TG/DTA), Scanning electron microscopy (SEM) was used to characterize the microstructure, porosity, and remaining biomass of the reduction product. Results show that: the reduction of iron ore by biomass starts at about 400 °C; the activation energies of H2 reduction in the initial and final stages are 2.54–4.68 kJ/mol and 56.69–85.36 kJ/mol, respectively; addition of biomass in pellets could ensure the carbon content and porosity of the reduction product; besides, reduction of 12% biomass pellets at 950 °C and 40% H2–60% N2 atmosphere is considered as the optimal reduction condition in this study, the final relative mass loss is 97.90%.

Fabrication of Copper(II)-Coated Magnetic Core-Shell Nanoparticles Fe3O4@SiO2: An Effective and Recoverable Catalyst for Reduction/Degradation of Environmental Pollutants

In this work, we report the synthesis of a magnetically recoverable catalyst through immobilizing copper (II) over the Fe3O4@SiO2 nanoparticles (NPs) surface [Fe3O4@SiO2-L–Cu(II)] (L = pyridine-4-carbaldehyde thiosemicarbazide). Accordingly, synthesized catalysts were determined and characterized by energy dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), vibrating sample magnetometer (VSM), field emission scanning electron microscopy (FESEM), and thermogravimetric-differential thermal analysis (TG-DTA) procedures. The [Fe3O4@SiO2-L–Cu(II)] was used for the reduction of Cr(VI), 4-nitrophenol (4-NP) and organic dyes such as Congo Red (CR) and methylene blue (MB) in aqueous media. Catalytic performance studies showed that the [Fe3O4@SiO2–L–Cu(II)] has excellent activity toward reduction reactions under mild conditions. Remarkable attributes of this method are high efficiency, removal of a homogeneous catalyst, easy recovery from the reaction mixture, and uncomplicated route. The amount of activity in this catalytic system was almost constant after several stages of recovery and reuse. The results show that the catalyst was easily separated and retained 83% of its efficiency after five cycles without considerable loss of activity and stability.

Green Synthesized Silver Nanoparticles Using Lactobacillus Acidophilus as an Antioxidant, Antimicrobial, and Antibiofilm Agent Against Multi-drug Resistant Enteroaggregative Escherichia Coli.

The present study was envisaged to employ the green synthesis and characterization of silver nanoparticles (AgNPs) using the potential probiotic strain Lactobacillus acidophilus, to assess its antibacterial as well as antibiofilm activity against multi-drug-resistant enteroaggregative Escherichia coli (MDR-EAEC) strains and to investigate their antioxidant activity. In this study, AgNPs were successfully synthesized through an eco-friendly protocol, which was then confirmed by its X-ray diffraction (XRD) pattern. A weight loss of 15% up to 182°C with a narrow exothermic peak between 170°C and 205°C was observed in thermogravimetric analysis-differential thermal analysis (TGA-DTA), while aggregated nanoclusters were observed in scanning electron microscopy (SEM). Moreover, the transmission electron microscopy (TEM) imaging of AgNPs revealed a spherical morphology and crystalline nature with an optimum size ranging from 10 to 20nm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of green synthesized AgNPs against the MDR-EAEC strains were found to be 7.80mg/L and 15.60mg/L, respectively. In vitro time-kill kinetic assay revealed a complete elimination of the MDR-EAEC strains after 180min on co-incubation with the AgNPs. Moreover, the green synthesized AgNPs were found safe by in vitro haemolytic assay. Besides, the green synthesized AgNPs exhibited significant biofilm inhibition (P < 0.001) formed by MDR-EAEC strains. Additionally, a concentration-dependent antioxidant activity was observed in 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays. Hence, this study demonstrated potential antibacterial as well as antibiofilm activity of green synthesized AgNPs against MDR-EAEC strains with antioxidant properties and warrants further in-depth studies to explore it as an effective antimicrobial agent against MDR infections.

Electrical Conductivities of Narrow-Bandgap Polymers with Two Types of π-Conjugated Post-Crosslinking.

Bandgap energy is one of the most important properties for developing electronic devices because of its influence on the electrical conductivity of substances. Many methods have been developed to control bandgap, one of which is the realization of conducting polymers using narrow-bandgap polymers; however, the preparation of these polymers is complex. In this study, water-soluble, narrow-bandgap polymers with reactive groups were prepared by the addition–condensation reaction of pyrrole (Pyr), benzaldehyde-2-sulfonic acid sodium salt (BS), and aldehyde-containing reactive groups (aldehyde and pyridine) for post-crosslinking. Two types of reactions, aldehyde with p-phenylenediamine and pyridine with 1,2-dibromoethylene, were carried out for the π-conjugated post-crosslinking between polymers. The polymers were characterized by proton nuclear magnetic resonance (1H-NMR), thermogravimetric/differential thermal analysis (TG/DTA), UltraViolet-Visible-Near InfraRed spectroscopy (UV-Vis-NIR), and other analyses. The bandgaps of the polymers, calculated from their absorption, were less than 0.5 eV. Post-crosslinking prevents resolubility and develops electron-conducting routes between the polymer chains for π-conjugated systems. Moreover, the post-crosslinked polymers maintain their narrow bandgaps. The electrical conductivities of the as-prepared polymers were two orders of magnitude higher than those before the crosslinking.

Electrical, optical, and mechanical properties of modified Czochralski grown organic 4-nitrobenzaldehyde single crystal

Growing large crystals of organic compounds with low melting points is a challenge but it was resolved by suitable modifications of the Czochralski (CZ) technique in the present study. A nonlinear optical single crystal of 4-nitrobenzaldehyde (4-NB) with a cylindrical shape, length of 2.5 cm, and diameter of 3 mm was successfully grown using an inexpensive modified CZ crystal growth technique at a temperature of 106 °C. The crystal structure and lattice parameters of the as-grown crystal were determined by single crystal and powder X-ray diffraction analyses. Intermolecular interactions were studied in the 4-NB crystal based on the Hirshfeld surface and two-dimensional fingerprint plot. The presence of various functional groups in the as-grown crystal was confirmed by Fourier transform infrared spectroscopy and nuclear magnetic resonance (1H and 13C) spectroscopy. The thermal behavior of the 4-NB crystal was analyzed by thermogravimetric analysis and differential thermal analysis. High transparency (75%) with an optical band gap of 3.34 eV and lower cut-off of 370 nm were confirmed by ultraviolet–visible–near infrared spectroscopy. The temperature-dependent dielectric behavior was determined for the 4-NB crystal at a constant frequency of 5 kHz. The mechanical properties of the 4-NB single crystal were analyzed based on the Vickers microhardness and void analysis, which confirmed the soft nature of the crystal. The modified CZ technique allowed us to obtain disk-shaped organic 4-NB crystals for use in optical applications.

Hydrolytic, thermal and radiation stability of modified urea-formaldehyde composites: Influence of montmorillonite particle size

Urea-formaldehyde (UF) composites with a formaldehyde/urea (FA/U) ratio = 0.8 and different particle sizes of montmorillonite (MMT), namely UF/KSF and UF/K10 were synthesized. The hydrolytic stability of modified UF composites was determined by measuring the content of the liberated formaldehyde of modified UF composites after acid hydrolysis. The synthesized modified UF composites were irradiated (50 kGy) and the effect of γ–irradiation was evaluated on the basis of these thermal behaviors. The thermal behavior was studied by non-isothermal thermo-gravimetric analysis (TG), differential thermo-gravimetry (DTG), and differential thermal analysis (DTA) supported by data from Fourier transform infrared spectroscopy (FTIR). The minimum percentages of free (0.4%) and liberated (1.2%) formaldehyde were obtained in the UF/KSF composite. The modified UF/KSF composite shows better radiation resistance than the modified UF/K10 composite. The shift of temperature values for the selected mass losses (T5%) to higher temperatures indicates an increase in the thermal stability of the UF/K10 composite after γ–irradiation. γ–irradiation causes a decrease in the absorption intensity of bands in the FTIR spectrum of a modified UF/KSF composite and an increase in the absorption intensity of bands in the FTIR spectrum of a modified UF/K10 composite.

The monomers and polymers of azomethine-based thiocarbohydrazones: Fluorescent activities, fluorescence quantum yields of polymers in water and DMF solutions

In this study, a family of azomethine-based thiocarbohydrazone monomers and polymers prepared and their structurally characterized by FT-IR, 1H–13C NMR and UV–Vis techniques. The electrochemical behaviors, fluorescent activities, thermal characteristics, antioxidant effectiveness of synthesized compounds were determined by cyclic voltammetry (CV), fluorescence (FL) spectroscopy, thermogravimetric-differential thermal analysis (TG-DTA), differential scanning calorimeter (DSC) and CUPRAC techniques, respectively. Fluorescence quantum yields of Poly-SATCH, Poly-BSATCH, Poly-MSATCH, Poly-NATCH were calculated to be 4.1, 9.4, 11.4 and 7.4 % in 0.025 mg mL−1 concentrations in DMF solutions in the range of 3 nm slit at 440, 420, 400 and 340 nm, respectively. The antioxidant values of monomer and polymers were changed between 0.30 ± 0.029 and 3.54 ± 0.719 against CUPRAC technique. The glass transition temperatures of Poly-SATCH, Poly-BSATCH, Poly-MSATCH and Poly-NATCH were found to be 116, 134, 138 and 139, respectively.

Heat Treatment of Geopolymer Samples Obtained by Varying Concentration of Sodium Hydroxide as Constituent of Alkali Activator

In this paper, raw natural metakaolin (MK, Serbia) clay was used as a starting material for the synthesis of geopolymers for thermal treatment. Metakaolin was obtained by calcination of kaolin at 750 °C for 1 h while geopolymer samples were calcined at 900 °C, which is the key transition temperature. Metakaolin was activated by a solution of NaOH of various concentrations and sodium silicate. During the controlled heat treatment, the geopolymer samples began to melt slightly and coagulate locally. The high-temperature exposure of geopolymer samples (900 °C) caused a significant reduction in oxygen, and even more sodium, which led to the formation of a complex porous structure. As the concentration of NaOH (6 mol dm−3 and 8 mol dm−3) increased, new semi-crystalline phases of nepheline and sanidine were formed. Thermal properties were increasingly used to better understand and improve the properties of geopolymers at high temperatures. Temperature changes were monitored by simultaneous use of thermogravimetric analysis (TGA) and differential thermal analysis (DTA). The loss of mass of the investigated samples at 900 °C was in the range of 8–16%. Thermal treatment of geopolymers at 900 °C did not have much effect on the change in compressive strength of investigated samples. The results of thermal treatment of geopolymers at 900 °C showed that this is approximately the temperature at which the structure of the geopolymer turns into a ceramic-like structure. All investigated properties of the geopolymers are closely connected to the precursors and the constituents of the geopolymers.

Effect of thermal crosslinking process on membrane structure and PEM fuel cell applications performed with SPEEK-PVA blend membranes

One of the promising options in the pursuit of clean and sustainable energy is fuel cell technology. PEM fuel cell stands out among fuel cell technologies due to its high efficiency, compactness, and ability to be used in portable applications. SPEEK (with different sulfonation degrees) and PVA blend membranes, which are thought to create a good synergy for PEM fuel cell, were prepared by using the solution casting method. As a result of the weight loss experiments, it was understood that the membranes dissolve in water regardless of the degree of sulfonation. Thermal crosslinking was carried out to prevent the membrane dissolution in water, which is in continuous contact with water in the fuel cell. Dissolution was mostly prevented by means of the thermal crosslinking process. Changes in the physical, chemical, and mechanical structure of the membrane after thermal crosslinking were comparatively determined by fourier transform infrared (FTIR), thermogravimetric analysis – differential thermal analysis (TGA-DTA), differential scanning calorimetry (DSC), water uptake capacity, swelling property, ion exchange capacity (IEC), dynamic mechanical analysis (DMA), electrochemical impedance analysis and oxidative stability. In addition, single-cell performance tests were performed with the membrane that gave the best results in the characterization analyses. Analysis results showed that thermal crosslinking prevented the dissolution of membranes in water ingreat extent. In addition, it was determined that the thermally crosslinked membranes had a more stable structure.

Facile synthesized NaGdF4 :Yb,Er peanut-shaped, highly biocompatible, colloidal upconversion nanospheres.

A facile method was used for the synthesis of peanut-shaped very emissive NaGdF4 :Yb, Er upconversion nanospheres (UCNSs) at lower temperatures with uniform size distribution. Crystallographic structure, phase purity, morphology, thermal robustness, biocompatibility, colloidal stability, surface chemistry, optical properties, and luminesce properties were explored by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), zeta potential, thermogravimetric/differential thermal analysis (TGA/DTA), Fourier-transform infrared (FTIR), ultraviolet (UV)-visible and photoluminescence spectroscopic tools. XRD pattern verified the construction of a single-phase, highly-crystalline NaGdF4 phase with a hexagonal structure. Peanut-shaped morphology of the sample was obtained from SEM micrographs which were validated from high-resolution TEM images, to have an equatorial diameter of 170 to 200 nm and a length of 220 to 230 nm, with irregular size, monodispersed, porous structure, and rough surface of the particles. The positive zeta potential value exhibited good biocompatibility along with high colloidal stability as observed from the absorption spectrum. The prepared UCNSs revealed high dispersibility, irregular size peanut-shaped morphology, rough surface, good colloidal stability, and excellent biocompatibility in aqueous media. A hexagonal phase NaGdF4 doped with ytterbium (Yb) and erbium (Er) UCNSs revealed the characteristics of highly dominant emissions located at 520-525, 538-550, and 659-668 nm corresponding to the 2 H11/2 → 4 I15/2 , 4 S3/2 → 4 I15/2 , and 4 F9/2 → 4 I15/2 transition of Er3+ ions, respectively, as a result of energy transfer from sensitizer Yb3+ ion to emitter Er3+ ion.

Cross-Linked Hydrogels Based on PolyNIPAAm and Acid-Activated Laponite RD: Swelling and Tunable Thermosensitivity.

The effects of acid activation of Laponite RD (Lap) on the structure and properties of activated Lap nanoparticles (aLap) and the properties of polyNIPAAm hydrogels physically cross-linked by aLap have been studied. The acid activation of Lap by the sulfuric acid was done using the concentration of sulfuric acid within the interval Ca = 0.525-14.58% for 10 h. For slightly activated samples (Ca ≤ 1.25 wt %), the significant increase of the specific surface area (by ≈1.56 times) was accompanied with a significant decrease in both the values of the specific heat of immersion in water and n-decane. However, the hydrophilic properties of all samples S0-S5 were still observed. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) data, Fourier transform infrared (FTIR) spectra, and X-ray diffraction (XRD) patterns demonstrated that the acid activation resulted in the destruction of the crystal lattice of Lap, leaching of magnesium and lithium, and formation of the amorphous phases. Moreover, the acid activation significantly affected aggregation and negative surface charges of the aLap faces in aqueous suspension. The effects of aLap on the swelling properties and cooperativity in the phase transitions of polyNIPAAm hydrogels cross-linked by aLap are also discussed. It was demonstrated that an increase in Ca resulted in a significant increase in the equilibrium degree of swelling of the hydrogels and a decrease in the hydrogel phase-transition temperature from the swollen phase to the shrunken phase.

Synthesis of chitosan-coated magnetite nanoparticles using co-precipitation method for copper(II) ions removal in aqueous solution

PurposeThe purpose of this paper is to focus on the removal of copper(II) ions from aqueous model salt solution by using chitosan-coated magnetite nanoparticles.Design/methodology/approachThe chitosan-coated magnetite nanoparticles were characterized using X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and thermogravimetric differential thermal analysis. The adsorption of Cu(II) by using magnetite nanoparticles as an adsorbent was investigated under different adsorption conditions. The parameters studied were contact time, adsorbent dose and initial concentrations.FindingsThe sorption capacities of prepared samples were studied for the removal of Cu2+ ions from aqueous model solutions with varying experimental conditions of the initial metal concentration, contact time and dosage. It is found that the removal percent of Cu2+ ions increases with an increase in initial metal concentration, contact time and amount of dosage.Originality/valueBased on the obtained results, this study recommends that chitosan-coated magnetite nanoparticles can also be applied for removal of some heavy metal ions and/or organic compounds in aqueous solution. It is recommended that this study be shared with the polymer-based nanomaterial researchers, especially material science.

Synergistic effects of polyaniline/poly(methyl methacrylate)/carbon nanotubes in nanocomposite polymer substrate electrodes for solar energy applications

Unique polyaniline (PANI)/poly(methyl methacrylate) (PMMA)/multiwalled carbon nanotubes (MWCNTs) nanocomposite polymer substrate electrodes (NPSEs) were prepared using in situ polymerization. PMMA microbeads (10 mm) were also added as fillers inside the NPSEs during polymerization. Different weight percentages of MWCNTs (1, 2, and 5 wt.%) were added to the NPSEs. The surface morphology of the PANI/PMMA/MWCNTs NPSEs was studied by scanning electron microscopy, Fourier transform infrared, and X-ray diffraction. Thermal stability was studied by thermo-gravimetric analyses and differential thermal analysis. Meanwhile, the four-probe analyzer and the solar simulator determined the electrical conductivities and photovoltaic parameters of the NPSEs based solar devices. The synthesized NPSEs with optimized compositions PANI/PMMA (1%)–MWCNTs (5%) showed superior photovoltaic performance along with improved thermal and electrical conductivities. Therefore, these NPSEs possess a future potential for the fabrication of solar devices in the field of solar energy applications.

Solid forms and β-cyclodextrin complexation of turinabol.

4-Chloro-17β-hydroxy-17α-methylandrosta-1,4-dien-3-one (C20H27ClO2), known as turinabol, is a synthetic anabolic-androgenic agent which belongs to the steroid class. Recrystallization from various solvents was performed and the following new solid forms of turinabol were obtained: the hemihydrate (C20H27ClO2·0.5H2O), the anhydrous form (C20H27ClO2), the multicomponent acetic acid hydrate (2C20H27ClO2·C2H4O2·H2O) and the 2,2,2-trifluoroethanol hemisolvate (C20H27ClO2·0.5C2H3F3O). The absolute structures were determined by single-crystal X-ray diffraction. The starting hemihydrate form contains one turinabol molecule in the asymmetric unit, while the others contain two molecules in the asymmetric unit. Structural features were investigated in terms of the conformational analysis of the steroid skeleton rings and intermolecular interactions. The magnitudes, the nature of the crystal structure energies and the intermolecular interactions were also evaluated. Complexation with β-cyclodextrin was performed and the obtained complex was investigated using powder X-ray diffraction, Fourier-transform infrared (FT-IR) spectroscopy and differential thermal analysis/thermogravimetric analysis (DTA/TGA).

Structure Determination, Mechanical Properties, Thermal Stability of Co2MoB4 and Fe2MoB4.

The precise determination of atomic position of materials is critical for understanding the relationship between structure and properties, especially for compounds with light elements of boron and single or multiple transition metals. In this work, the single crystal X-ray diffraction is employed to analyze the atomic positions of Co2MoB4 and Fe2MoB4 with a Ta3B4-type structure, and it is found that the lengths of B-B bonds connecting the two zig-zag boron chains are 1.86 Å and 1.87 Å, but previously unreported 1.4 Å. Co and Fe atoms occupy the same crystallographic position in lattice for the doped samples and the valence is close to the metal itself, and Co/Fe K-edge X-ray Absorption Fine Structure(XAFS) spectra of borides with different ratios of Co to Fe are collected to detect the local environment and chemical valence of Co and Fe. Vickers hardness and nano indentation measurements are performed, together with the Density Functional Theory (DFT) calculations. Finally, Co2MoB4 possess better thermal stability than Fe2MoB4 evaluated by Thermogravimetric Differential Thermal Analysis (TG-DTA) results.

Systematical Study on the Influencing Factors of Synchronous Thermal Analyses of Samples-Taking the Chalcanthite as an Example.

Thermal analysis is widely used for the measurement of the relationship between temperature and physical properties of the materials. Many studies have reported different thermal analysis methods, including thermogravimetry (TG), derivative thermogravimetry (DTG), differential heat analysis (DTA), and differential scanning calorimetry (DSC), but few comprehensively studied the factors influencing TG-DTA by the combined thermogravimetry–differential thermal methods. In this study, taking chalcanthite as the research object, the thermogravimetric–differential thermal analyses were systematically conducted by using synchronous thermal analyzer technology. The results demonstrate that 1) DTA curves of low- and medium-weight chalcanthite show five dehydration endothermic peaks, while TG curves do not display obvious weight-loss steps; DTA and TG curves of high-weight chalcanthite samples, on the other hand, illustrate three endothermic peaks, indicating three-step loss of crystalline water; 2) higher weight of samples may cause longer time of internal heat transfer and larger temperature gradient, consequently resulting in the expansion of DTA peak shape and the decline of resolution as well as the increase of the peak temperature; 3) the weight-loss deviation between the measured and theoretical data is relatively higher in the low-weight samples than that in the medium- and high-weight samples; 4) the heating rate can increase the DTA curve peak and thermal inertia and the temperature at the thermodynamic equilibrium, causing the temperature lagging behind and the overall peak moving toward high temperature; 5) sample grinding may destroy the structure of the crystal, thereby breaking the relatively weak chemical bond, and thus affects the structure of thermogravimetric–differential thermal analyses. These suggest that the sample weight, heating rate, and sample grinding probably have significant effects on the thermogravimetric–differential thermal analyses. Therefore, proper experimental conditions are needed to obtain the accurate results during the thermogravimetric–differential thermal analyses. This study can provide a basis and reference for future synchronous thermal analyses.

Green mediated combustion synthesis of copper zinc oxide using Eryngium planum leaf extract as a natural green fuel: Excellent adsorption capacity towards Congo red dye

In the present study, meso/microporous CuO/ZnO nanostructures were synthesized via a green mediated solution combustion method by Eryngium planum leaf extract as natural fuel for the first time. Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), dispersive X-ray spectroscopy (EDX), Fourier transform infrared spectrometer (FTIR), Thermogravimetric/differential thermal analysis (TGA/DTA), and N2 adsorption-desorption analyses were applied to characterize the as-prepared samples. The total pore volume and average pore diameter of the CuO/ZnO nanostructures were 0.06945 cm3/g and 4.76 nm, respectively. A batch adsorption test was conducted using the as-synthesized samples to evaluate their ability to remove congo red (CR) dye. In the following, the effective parameters in the adsorption of CR by CuO/ZnO nanostructures, including contact time, adsorbent dosage, pH of the solution, initial dye solution concentration, and temperature, were investigated in detail. Also, the kinetic, isotherm, and thermodynamic studies were evaluated. The results indicated that the intra-particle diffusion model (R2 = 0.9990) and pseudo-second-order model (R2 = 0.9998) are suitable models for describing the adsorption rate at the early (0–60 min) and later (60–240 min) times, respectively. According to the Langmuir isotherm model, the maximum adsorption capacity of CR by CuO/ZnO was found to be 357.14 mg/g. Moreover, the negative value for each of the parameters of ΔH° and ΔS° indicates that the adsorption at the solid/solution interface is exothermic and non-random during the process, respectively. Therefore, the proposed eco-friendly and inexpensive green synthesis method can be considered to develop new interesting materials to remove contamination from industrial wastewaters.